A concurrently filed, copending application of C. Hottinger, U.S. Ser. No. 178,482 entitled "ULTRASONIC IMAGING SYSTEM EMPLOYING REAL TIME MECHANICAL SECTOR SCANNER" and assigned to the assignee hereof, describes and claims a form of real time mechanical sector scanner wherein a positionally fixed, focusing transducer emits and receives ultrasound energy along an axis, and an oppositely facing sonic reflector or mirror is pivoted about a fulcrum on the axis, to reflect sonic energy between the transducer and the subject. Thus, beams between the reflection face and the subject lie in a different spatial plane than do beams between the transducer and the subject. In addition to setting forth the basic premise of such operation, the Hottinger application discloses respective embodiments wherein the mirror is located intermediate the transducer and the source of oscillatory motive power, and wherein the mirror is located "outboard" of the transducer relative to the source of oscillatory motive power. As stated in the Hottinger application, the former arrangement represents in essence the type of mechanical sector scanner as set forth in the instant application, and in relevant portion made the subject of the claims hereof.
It is an object of the present invention, given the basic design precepts entailed by the Hottinger application, to provide a relatively optimally designed sector scanner, especially suitable for abdominal soft tissue applications, but quite amenable to other applications as well, by locating the respective component parts in a mutually complimentary and overall more efficient arrangement.
It is a further object of the present invention to provide such designs which minimize load inertial forces attendant to oscillating mirrors, the number of rotary seals required to maintain the integrity of the fluid borne by the transducer head, and the overall mechanical complexity and structural bulk of the head.
It is a further object of the present invention to provide a stationary transducer, axially rotating mirror configuration wherein artifacts occasioned by mirror support systems are relatively minimized.